Automatic switch for telephones



Dec. 8, 1931. M. FUJITA 1,835,385

I AUTOMAT IC SWITCH FOR TELEPHONES Filed Aug. 21, 1929 Id A? rd ll Patented Dec. 8, 1931 MASA FUJI'IA, OF FUKUIKEN,"JAYAN i nii'rolvinri:oswiron ron'rnnnrnolvns 7 Application filed August 21, 1929, Serial No; 387,321, and in Japan August 25, 1928.

The invention relates to an. automatic switchto be provided in each of the telephones of a system wherein one or more tele- I phones are connected to the main telephone asbranchcs, for connecting one of them to the talking circuits automatically by removing the receiver from the prongs. Y Hereto'lore, a hand operating switch provided with buttons, the number of which corresponds to that of the branch telephones, has been provided at the main telephone so that, when one wishes to call by one or the branch telephones, it isnecessary to give a signal to the main telephone by a suitable means and to let somebody near the main telephone operate said switch to connect said branch telephone to the telephone circuits. If said switch is left so connected owing to carelessness of users, then the call-signal from thee change-office willbe received by said branch telephone but notby'the'main telephone, and so it is necessary to give a signal from said branch to the main.

By means of the automaticswitch according to the present invention, however, such diiticul ties have been overcome satisfactorily.

In the accompanying drawings, Fig. 1 shows a side section of a telephone wherein the automatic switch according to this inven tion is employed, and Fig. 2 is a wiring diagram of an example showing how the present invention is carried. out.

The automatic switch (3) is composed of three contact springs (3) (8) (3 supported by an insulator (2) attached to'a side wall of the casing The central spring (3. is made longer than the other two. One end of the hook switch leverpivoted at is pronged to form the sup [port for the receiver and the other end is tormed as shown in Fig. 1. When the weight of the receiver is upon the prongs, the lever (4;) is depressed so that the projection (5) provided at one end of said lever acts to 4 bring the central spring (3) into contact to ward and the central spring (3) comes into contact with the spring (3") by its elasticity.

The end portion of theproj ection (5) which comes into contact withthe spring; (3") is made ofinsulating material; i i A wiring diagramof a system wherein the automatic switch according to this invention is provided is shown, bywayof example, in Fig. 2. In this diagram, only three telephones including the main telephone, are shown, but the system can be extended to 'include as large a number asma y be desired,

. Branch lines (a) (b) from the common return .wire are connected to the binding post(8) of the main telephone (A) and the branch telephones and (C) separately. The wire (L) is connected to the binding post (9) oi the ina in telephone (A); The

binding post is connected to the central spring The central spring (3')is in contact with the spring The spring (3) is connected to the binding post (9) and the latter is connectedto the binding post (9) of the telephone (13). The inside connections of the telephones(B) and (C) are the same, as showninthe main telephone (A). l n short, the wire (L)'c0nnectsthe springs (3) and (3) f the switch provided in each telephone in series.

As shown in Fig. 2, the terminals. and (9) oft-he main telephone are connected by a switch lever (10) while in the bra nch telephones and. switch levers (i0) occupy such a position as to break the connection between the terminals (9) and (9). Therefore, one can call: or talk with another by the main telephone as freely as usual and in this case i the automatic switch provided therein acts to disconnect automatically all the branch telephones from the talking circuits. V

lVhen one wishes to useone of the branch telephones, it sut'lices to remove the receiver from the prongs, and then the central spring 8) will; come into contact with the spring (37) so as to connect the telephone to the telephone circuits. 1; 1 i

Thus, in the main as wellas in thebranch telephones,- the. connection; to tlie telephone 229 circuits can automatically be effected simply by removing the receiver from the prongs.

In the above telephones, when the hook rises in response to a spring, the receiver being removed, the switch (B) composed oil three springs o erates to connect to the talking circuits. uch an action of the hook is the same as that of the hook employed in an ordinary tele hone. The device according to this invention does not interfere with the action of the hook but it rather tends to aid it.

The call-signal from the exchange ofiice closes the circuits from the wire (L),- the terminals (9) (9"), the polarized bell (11), the condenser (12), and the terminal (8), to the common-return (L) to actuate the bell (11) of the main telephone (A), while in the branch telephones the bells are not actuated because the connections between the terminals (9) (95) are broken.

If it is desired to receive the call-signal at one of the branch telephones, it will suflice to connect the terminals (9) (9) of the telephone by the switch lever (10) while the connection between the terminals (9) (97) of the main telephone (A) is broken.

-As mentioned above, while the main telephone (A) is employed, the connection between the springs (3) i (3) is broken to disconnect all other telephones from all the circuits, and if the receiver of the main telephone (A) is removed from-the prongs when one of the branch telephones is employed, the

message will be interrupted. Therefore, no

message can be stolen by others in the telephones of this system.

A special means is employed in this system for indicating to the other telephones that one of, them is being used.

Said device consists of a switch (15), an indicating lamp (17) or (17) and necessary wirings. The switch (15) is composed of three contact springs (15') (15) (15), the spring (15) being made longer than the other two (Fig. 1). The switch (15) is supported by an insulator (1 L) attached to a side wall (1) of the casing. l/Vhen the weight of the receiver is upon the prongs, the projection (16) provided at one end of the hook lever (4) acts to push thespring.(15). On the other hand, when the receiver is romoved from the prongs, the lever rises and the projection (16) displaces right-ward so that the spring (15) moves rightward by its elasticity and all the springs (15) (15") (15") come into contact with each other. The end portion of the projection (16) which comes into contact with the spring (15) is made of insulating material.

The indicating lamps (17) and (17) are provided separately in the main and branch telephones (Fig. 2) with a suitable electric In each telephone, the spring (15) is connected with the positive pole of said electric source through a line ((1). The common return wire (g) connects each one electrode of the indicating lamps (17) (17) and the negative pole of the electric source. The line (a) connects the springs (15) of all the telephones, the spring (15") of the main telephone and one electrode of each indicating lamp (17). The line (f) connects the springs (15) of the branch telephones and one electrode of the indicating lamp (17) of the main telephone (A).

Hence, while the main telephone (A) is be ing used, the springs (15) (15) (15) provided therein are in contact, electric current passes from'the line (d) to the line (6) so as to light all the lamps (17) bridged between the line (6) and the common return (g).

WVhileone oi the branch telephones is being used, electric current will pass between the lines (d) (c) (f) so as to light all the lamps (17) bridged between the line (6) and the common return (g) and the lamp (17) between the line and the common return (9). In other words, while the main telephone A) is being used, all the indicating lamps except (17) are lighted, and while one of the branch telephones is being used, all the lamps (17) (17) are lighted.

By these means, when a message to one of the branch telephones is received by the main telephone and the signal is given from the main to the branch, and the receiver of the telephone is removed from the prongs, the

indicating lamp at the main telephone will be lighted, which indicates that. the signal has been received, and so the man at the main telephone may hang the receiver on the prongs to connect the branch telephone circuits in a simple manner.

Various modifications of this invention could be devised within the limits of the invention.

Having now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed, I declare that what I claim is:

1. In a telephone system, a main telephone and a plurality of branch telephones, connections between. said branch telephones and 1 the main telephone, and an automatic switch associated with each of the telephones and directly controlling the connections between the telephones whereby exclusive communication between one of the branch telephones and the telephone line is provided for, said switch consisting of three elastic contacts wherein two of them are in contact, connected in series with the telephone line and the other is isolated from the other two, and when the receiver is lifted one of the first two contacts is brought into contact with said other contact for exclusive connection between the telephone and the line.

2. In a telephone system, a main telephone Lit" and a plurality of branch telephones, an automatic switch of each telephone for establish ing exclusive connection between one of said telephones and the telephone line and another automatic switch of each telephone for controlling circuits including means for indi eating to the others that one telephone is engaged, said switches being mechanically operated by the movement of the hook lever, and consisting of three elastic contacts, one of which makes and breaks contacts with a central one of two other contacts, said central contact being always connected to one or the other of the contacts whereby on connection with the lever with the central contact, a con-' nection is made with one of the other contacts to complete a circuit in a branch phone.

3. In a telephone system, a main telephone and a plurality of branch telephones, an automatic switch of each telephone consisting of three elastic contacts wherein two of them are in contact, connected in series with a telephone line and the other is kept isolated from the former when the receiver is mounted on the hook, but when the receiver is removed from the hook, the first two contactsare disconnected from each other and one of them is brought into contact with the other so as to establish exclusive connection between one telephone and the telephone line, and another automatic switch of each telephone consisting of three elastic contacts which are isolated from one another when the receiver is mounted on the hook but brought into contact when the receiver is removed from the hook so as to close the circuits including means for indicating that one telephone is engaged.

4. In a telephone system having a main telephone and a plurality of branch telephones; an automatic switch consisting of a telephone line, a receiver hook lever, three elastic contacts with two of them in contact connected in series with said telephone line whereby to be in operative connection with another phone, and means intermediate with the telephone line circuit at each station for making and breaking the circuit between two of the contacts when the telephone receiver is lifted OK the hook, and the connection is broken between the first two contacts and one of them is brought into connection with the other so that exclusive communication is maintained between two stations.

In testimony whereof I hereunto aflix my signature.

MASA FUJITA. 

